The 2012 Olympic silver medalist in the 10,000m was racing in Brussels, a month after the games, in what was supposed to be her last race of the season. About 70 meters from the finish line of the Diamond League 5,000m, her spikes clipped the rail. Trying to stay upright, Kipyego landed awkwardly on her left foot. The sound was a giveaway. "I just knew I had broken something," she says.

She limped to the finish line and took an early morning flight back to her home in Eugene, Ore., where she trains with Oregon Track Club Elite. The next day, an X-ray confirmed her fears: She had broken her calcaneus, the bone in the heel. Kipyego wore a walking boot for two months, then through the winter she became familiar with the pools in Eugene, where she would aqua jog, attempting to maintain some fitness. From the pool, she graduated to the underwater treadmill and then the AlterG.

But it wasn't a smooth road back to competition. In March, the heel was sore. A CT scan revealed a stress fracture at the site of the original break.

It was clear that her outdoor track season--and any chance of representing her native Kenya at the 2013 world championships in Moscow--would be lost. Kipyego had never been injured through her college days at Texas Tech University and her pro running career, and suddenly she was missing an entire year.

"I struggled emotionally," Kipyego, now 28, says. "I had some awful days, especially the first month after I was diagnosed. There's nothing worse than sitting on the sidelines watching people competing and you can't really do anything about it."

At that point, Kipyego had a cast put on her foot, and she ceased cross-training. "I've always been a great champion of listening to your body," she says. "And when I got injured the second time, I knew that somehow my body was telling me something--that I wasn't fit to come back, or that I was not healthy in general and I needed a break."

Kipyego did no physical activity for two months. When she returned to running in June, she alternated a minute of running with a minute of walking for 10 minutes total and followed up with a day off. By July she was up to 5 minutes of continuous running. Then 10. By August, she had reached 30 minutes. "It sounds ridiculous," she says, "but it was necessary for me to do the smaller things, the 5 minutes, tick off the smaller boxes along the way."

By October, she was up to 60 miles per week--well below the 85–90 she normally reaches in the fall after a summer track season. But she was completely pain-free, and returned to racing in New York at the Dash to the Finish Line 5K, where she was fourth in 15:49. By the end of 2013, she had reached 75 miles per week and resumed consistent workouts with long intervals and short rest, like 8 × 1K in 3:15 with 90 seconds rest. "Nothing really fast," she says.

After a run, Kipyego puts her full energy into recovering. She'll return to her house after a morning workout and immediately consume some protein--often in the form of an egg sandwich--and spend the next several hours on her couch, reclining and watching TV. She takes two-hour naps most afternoons, unless she has a commitment. "I try to consciously rest and rejuvenate," she says.

Kipyego is notorious for running her easy days at a slow pace. The bulk of her mileage, often an 8-mile run in the morning and a 5-mile run in the afternoon, is at 8:30 per mile. "I work pretty hard on the workout days, but I step off the gas when I need to," she says. She cuts an easy day short if she is tired, and she never tallies her mileage before Sunday. "I have an idea, but I try not to focus on miles, because it's easy to get carried away," she says.

These habits have been with her since she started running in the junior ranks in Kenya. Which makes it all the more surprising that her injury took so long to heal. But with the next Olympics still three years away, she'll remember the frustration of 2013 as a freak accident. She'll use the same principle that has guided her success so far: "You let your body tell you," she says. "It will let you know exactly what's happening."